[Bug] Wrong Authority created in CreateAuthorityForRequest method call

[wziska]

Which Version of MSAL are you using ?
MSAL 4.7.1

Platform
net45, xamarin android, xamarin iOS

What authentication flow has the issue?
Any

Is this a new or existing app?
The app is in production, I haven't upgraded MSAL, but started seeing this issue

Repro

            var publicClientBuilder = PublicClientApplicationBuilder.Create(ClientId)
                .WithLogging((level, msg, pii) => { Console.WriteLine(msg); });

            var clientApp = publicClientBuilder.Build();

            var getTokenResult = await clientApp.AcquireTokenInteractive(Scopes)
                 .WithPrompt(Prompt.SelectAccount)
                 .WithB2CAuthority(CreateAuthorityString("https://login.microsoftonline.com/tfp/<tentant>.onmicrosoft.com/<policy>"))
                 .ExecuteAsync();

Expected behavior
As I added WithB2CAuthority I expect that in Authority.CreateAuthorityForRequest method new B2CAuthority class is instantiated.

Actual behavior
AadAuthority instance is created in Authority.CreateAuthorityForRequest call.

Possible Solution
It seems this behavior was introduced in #1456
Accordingly to comment in

microsoft-authentication-library-for-dotnet/src/client/Microsoft.Identity.Client/Instance/Authority.cs

Line 37 in faabb9c

/// 2. If there is a request authority, try to use it.

we should check AuthorityType in requestAuthorityInfo (if exists). Now requestAuthorityInfo is ignored and only configAuthorityInfo.AuthorityType is considered .

[bgavrilMS]

Ack, I can see the problem. To work around it you need to specify an authority when you create the PublicClientApplication. It doesn't matter the policy, as the policy specified in AcquireTokenInteractive will be taken into account.

[trwalke]

Fixed in 4.9.0
https://github.com/AzureAD/microsoft-authentication-library-for-dotnet/releases/tag/4.9.0